Grayscale image: Difference between revisions
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=={{header|Ada}}==
<code ada>
type Grayscale_Image is array (Positive range <>, Positive range <>) of Luminance;
</
Conversion to a grayscale image:
<code ada>
function Grayscale (Picture : Image) return Grayscale_Image is
type Extended_Luminance is range 0..10_000_000;
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return Result;
end Grayscale;
</
Conversion to a color image:
<code ada>
function Color (Picture : Grayscale_Image) return Image is
Result : Image (Picture'Range (1), Picture'Range (2));
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return Result;
end Color;
</
=={{header|C}}==
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Definition for a grayscale image.
<code c>
typedef luminance pixel1[1];
typedef struct {
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luminance *buf;
} grayimage_t;
typedef grayimage_t *grayimage;
</code>
The same as <tt>alloc_img</tt>, but for grayscale images.
<code c>
{
grayimage img;
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img->height = height;
return img;
}
</code>
Convert from ''color'' image to ''grayscale'' image.
<code c>
{
unsigned int x, y;
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}
return timg;
}
</code>
And back from a ''grayscale'' image to a ''color'' image.
<code c>image tocolor(grayimage img)
{
unsigned int x, y;
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}
return timg;
}
</code>
'''Notes'''
* <tt>tocolor</tt> and <tt>tograyscale</tt> do not free the previous image, so it must be freed normally calling <tt>free_img</tt>. With a cast we can use the same function also for grayscale images, or we can define something like
<code c>
</code>
* ''Luminance'' is rounded. Since the C implementation is based on unsigned char (256 possible values per components), L can be at most 255.0 and rounding gives 255, as we expect. Changing the color_component type would only change 256, 255.0 and 255 values here written in something else, the code would work the same.
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Conversion to a grayscale image:
<code ocaml>
let width = Bigarray.Array2.dim1 r_channel
and height = Bigarray.Array2.dim2 r_channel in
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done;
done;
(gray_channel)
</code>
Conversion to a color image:
<code ocaml>
let width = Bigarray.Array2.dim1 gray_channel
and height = Bigarray.Array2.dim2 gray_channel in
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r_channel,
g_channel,
b_channel)
</code>
=={{header|Vedit macro language}}==
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